[0913]

My problem has two parts:
1. My original brake issue started with what I thought was warped rotors. After driving at about 45 MPH and above for about 15 minutes and then lightly applying the brake, I expierienced excessive shuddering throughout the vehicle. The syptom seemed like one of warped rotors. There was no feedback in the wheel but never the less I thought they could be out since the truck has 82,000 on it. The tires on it were Firestone Steeltex R4s 265/75/16. I replaced them with BFG AT TA 265/75/16's along with having the rotors turned by my trusted local mechanic. Needless to say, the vibration shudder is still there even after the brakes were turned. In order to narrow down the problem, I took the truck out on the freeway at night and held the e-brake release latch while stepping on the e-brake pedal. This did produce some pulsing and could be the source as it is a solid, leaf sprung rear axle. I am going to have the drums turned to see if this solves anything. Suggestions? This is very annoying as I pull a 30 foot trailer with this rig and need to be confident in my brakes.
2. After getting the truck back, now I have a new brake problem. At slow speed stopping (creeping through a parking lot), I periodically get a groan from the front brakes along with a little pedal fade and what feels like ABS engagement. This does not happen all of the time and is usually most notable when the brakes are cold. My mechanic assures me it is due to the pads seating on the new surface and that it will go away but I am not convinced. I have driven about 300 city miles since the brakes were done. This problem only surfaced after the rotors were turned and there was no evidence of it before then. Is it possible that they disconnected something when the pulled the rotor assembly? I am aware that on the 2500's, the rotor assembly also contains the components for the hub assembly (bearings etc). Are there ABS components that could have been altered by this process?

Other than the instances listed, the brakes stop great and I have had no problems during pannic stops at under 45 MPH.

If anyone knows something that can save me long expensive diagnostics please reply.

Thank you!